The present disclosure relates to an image forming apparatus and an image forming method, particularly to an image forming apparatus and an image forming method configured to erase job data in a storage part by overwriting.
There exists an image forming apparatus, such as a multifunction peripheral (MFP), capable of executing a job such as a print job and a scan job.
Such an image forming apparatus executes a plurality of jobs transmitted from multiple users by using multi-process, such as time sharing processing, and multithread.
The image forming apparatus, in view of security, executes such operation that data of a previously output job (hereinafter, often called as job data) containing image data or the like stored in a storage part, such as a HDD (Hard Disk Drive), is erased by writing a value of “0” or random digits on the data.
Here, referring to FIG. 9, an example of an operation to erase job data will be described.
Since it takes a long period to erase job data, an image forming apparatus executes such operation that the erasing of the job data is suspended at which time a job execution is started and the erasing of the job data is resumed at which time the job execution is completed.
Therefore, since it is impossible to erase the job data during the executing of the job, it takes a long period to erase unnecessary data.
For example, in the image forming apparatus, when image data stored in a memory is automatically erased, the erasing operation of image data having a high frequency of output among the written image data is delayed and image data having a low frequency of output is erased preferentially. This facilitates the highly important data to be remained in the memory constantly and thus enables to realize an effective data management.
For example, in an image input and output device applied to an image forming apparatus, an information of degree of importance is added to image data. When a record of image data input newly cannot be stored owing to insufficient capacity of the storage, the previously stored image data is erased based on the information of the degree of importance, thereby preventing interrupting the job owing to the insufficient capacity of the storage.
For example, an image data management device applied to an image forming apparatus sequentially stores and also sequentially reads image data in and from a hard disk in a storage part, and detects the hard disk working condition during the reading. And, based on the detected result, the image data management device controls so as to erase at least a part of the previously read data from the hard disk. This enables to execute the job, even if an input job has a large data size, while maintaining the storage condition of the job containing the previously stored image data.
However, the technique of the above-mentioned image forming apparatus is correspondent to an operation to erase an “index” of a file system in the storage part. That is, the technique cannot be applied to an operation requiring a long period such as an operation to erase unnecessary job data output previously by overwriting.
For example, an image controlling device applied to an image forming apparatus, when a predetermined area among divided areas of a storage part is controlled prior to an usual image controlling preferentially, interrupts an erasing operation and executes a control operation to erase the information data itself for the predetermined area by the erasing part from the beginning at which time the usual image controlling is completed.
The image controlling apparatus executes the same operation as the operation shown in FIG. 9.
However, in the image forming apparatus executing the above-mentioned erasing operation, although the erasing operation in an area of the storage part is executed according to the erasing pattern and the priority, because the erasing operation is suspended during the execution of the job, the job data cannot be erased effectively.